For a detailed discussion on this genus, Diplandrorchis, and Holopogon, see Chen and Tsi (Acta Phytotax. Sin. 25: 329-339. 1987). One of us (Gale) believes that Tangtsinia nanchuanica is a peloric form of Cephalanthera falcata and that Tangtsinia should be considered congeneric with Cephalanthera.